Generally, various parts and systems are integrated in a vehicle and controlled by electronic control units that are configured to drive an actuator and the like based on, for example, signals detected by sensors and a processing result by a computer. Further, such electronic control units generally include a self-diagnosis function to diagnose whether in-vehicle devices such as sensors and actuators are being operated correctly. There is a known technique (for example in Patent Document 1) in which, when a result of the self-diagnosis shows that abnormality is detected, abnormality information such as a diagnosis code and freeze frame data are stored in the electronic control units so that the stored abnormality information are read out later by using a diagnosis tool in a service facility or the like to be used for analyzing a cause of the abnormality and the like. Further, in order to collect the abnormality information more effectively, when the abnormality information is detected, the detected abnormality information are transmitted to an analysis center and stored in a database in the analysis center so that the analysis center analyzes the abnormality of the vehicle.
However, if all the abnormality information is transmitted to the analysis center, namely, for example, abnormality information generated due to a simulated signal for simulating an abnormality in a service facility or abnormality information that is generated while parts are exchanged and that is not related to any abnormality are transmitted to the analysis center, the analysis center may not determine whether the transmitted abnormality information is based on an actual failure or a false alarm due to the simulated signal, the parts exchange, and the like, thereby making it difficult to analyze the causes of the abnormality.
To overcome the problem, a communication method is proposed (for example, in Patent Document 2) in which when the abnormality information is output to a diagnosis tool from a vehicle, the abnormality information is not transmitted to the analysis center. Namely, when the abnormality information is output to the diagnosis tool, it is regarded that the vehicle is in a service facility or the like to receive service, inspection, or repair. Therefore, it may become possible to prevent the transmission of the abnormality information related to the simulated signal and the parts exchange to the analysis center.    Patent Document 1: Japanese Patent Application Publication No. 2006-96325    Patent Document 2: Japanese Patent Application Publication No. 2005-41438